But now it has been alleged that the black sheep of the family is "heavily into partying with sizzurp".

The concoction is a mixture of codeine-based medicine and sugary drinks, consumed by users for the relaxing effect it has on the body.

“He feels completely estranged from his sisters and family. He really isn't in a good place”

A source close to Rob Kardashian

Rumours about his suspected drug use have been rife for months, but TMZ.com have reported that members of the Kardashian family have been contacting rehabilitation facilities on his behalf after alarming pictures emerged online.

The snaps seem to be taken at a house party, they show Rita Ora's former fling dragging on a suspicious looking cigarette.

He is seen sitting in front of a table laden with cups of purple liquid – which looks very similar to the intoxicating cough medicine, which also goes by the name of Purple Drank.

One of the beakers by Rob is even emblazoned with a logo that reads: "Codeine Boys".

According to Radar Online, a source revealed: "He feels completely estranged from his sisters and family. He really isn't in a good place.

TROUBLED: Rob is seen with a 'Codeine Boys' cup [SPLASH]

"Rob hasn't returned any of Khloe's phone calls or texts."

Kris Jenner has previously raised concerns about her son's wellbeing.

The momager said: "He's going to be okay. A lot of prayer, you know, he's such a great human being… he's my heart."